In an effort to grow, the company is trying to make the image-discovery site less U.S.-centric

In a bid to attract Internet users world-wide, image-discovery site Pinterest Inc. has learned a few valuable lessons. Among them: The French don’t want to see the Americanized recipes of beloved classic dishes such as the cassoulet, but they aren’t averse to non-Parisian fashion.

Such fickle tastes are complicating Pinterest’s expansion overseas, a critical effort to justify the six-year-old startup’s $11 billion valuation and eventually appeal to public-market investors.